Feasibility of in vivo (18)F-florbetaben PET/MR imaging of human carotid amyloid-beta

Amyloid-beta (A beta) peptides are involved in the inflammatory pathology of atherosclerosis. F-18-Florbetaben is a PET tracer for clinical imaging of cerebral A beta plaques in Alzheimer's disease (AD). We sought to determine whether specific uptake of F-18-florbetaben in the carotid arteries can be identified using a fully integrated hybrid PET/MRI system and whether this uptake is associated with clinical cardiovascular disease (CVD) risk factors.

Carotid F-18-florbetaben uptake was quantified as the mean of the maximum target-to-background ratio (meanTBRmax) in 40 cognitively impaired subjects (age 68.2 +/- 9.5 years) undergoing F-18-florbetaben PET/MRI to diagnose AD. Associations between carotid F-18-florbetaben uptake and several CVD risk factors were assessed by univariate analysis followed by a multivariate linear regression analysis. Furthermore, carotid F-18-florbetaben uptake was compared between patients with and without a positive cerebral A beta PET scan.

F-18-Florbetaben uptake was clearly visualized in the carotid arteries. Values of meanTBRmax corrected for the blood pool activity of the tracer showed specific F-18-florbetaben uptake in the carotid wall. Male gender was associated with carotid F-18-florbetaben uptake in the univariate analysis, and was found to be an independent predictor of F-18-florbetaben uptake in the multivariate regression analysis (standardized regression coefficient beta = 0.407, p = 0.009). Carotid F-18-florbetaben meanTBRmax in patients with a positive cerebral A beta scan did not differ from that in patients without cerebral A beta deposits.

Specific F-18-florbetaben uptake in human carotid arteries was detected. Male gender was identified as an independent clinical risk factor. Therefore, F-18-florbetaben PET/MRI might provide new insights into the pathophysiological process in atherosclerosis.